1. Field of the Invention
This invention relates to heavy-duty liquid detergent compositions, and in particular, to ones which are laundry detergents and ones which are designed so that they avoid the use of phosphates as builders and so that they also avoid the use of triethanolamine, a builder or alkalizing agent hitherto often considered especially useful and preferred in the making of compositions of the kind indicated above.
2. Description of the Prior Art
U.S. Pat. No. 4,079,078 may be taken as rather typical of prior-art teachings with respect to the making of a phosphate-free liquid laundry detergent composition. According to this patent, the use of triethanolamine is preferred.
U.S. Pat. No. 4,105,592 also relates to liquid detergent compositions, and it states that the use of excess free alkanolamine is considered desirable.
U.S. Pat. No. 3,456,176 relates to the making of liquid detergent compositions, and it says that in its final step of raising the pH of the composition to a value greater than 8.5, virtually any basic material capable of being used to reach that pH may be used. U.S. Pat. No. 3,395,215 contains a similar teaching to the effect that virtually any basic compound, preferably triethanolamine, may be used to neutralize a composition of this sort. U.S. Pat. No. 3,395,215 also indicates that there may be added to its composition a humectant, e.g., sorbitol.
U.S. Pat. No. 2,697,118 relates to N,N,N',N'-tetrakis(2-hydroxypropyl)ethylene diamine and similar compounds, and it teaches that such compounds are high-boiling bases and are valuable humectants.
A discussion of the problem of nitrosamines and how they have been found to be carcinogenic and undesirable in consumer products is found in the article of M. L. Douglass et al., "Chemistry of Nitrosamine Formation, Inhibition and Destruction", in Vol. 29 of the Journal of the Society of Cosmetic Chemists, pages 581 to 605 (September 1978).
To the inventor's knowledge, the prior art has been silent on the issues of (a) whether the above-indicated totally hydroxyalkylated alkylene diamines do, in fact, form nitrosamines in detectable amounts and (b) whether, in the liquid-laundry-detergent field, satisfactory performance results can be obtained when such totally hydroxyalkylated alkylene diamines are substituted for triethanolamine.